docs: def spksfs(body, et, idlen):
      # spksfs has a Parameter SIDLEN,
      # sounds like an optional but is that possible?
      """
      Search through loaded SPK files to find the highest-priority segment
      applicable to the body and time specified.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/spksfs_c.html
  
      :param body: Body ID.
      :type body: int
      :param et: Ephemeris time.
      :type et: float
      :param idlen: Length of output segment ID string.
      :type idlen: int
      :return:
              Handle of file containing the applicable segment,
              Descriptor of the applicable segment,
              Identifier of the applicable segment.
      :rtype: tuple
      """
      body = ctypes.c_int(body)
      et = ctypes.c_double(et)
      idlen = ctypes.c_int(idlen)
      handle = ctypes.c_int()
      descr = stypes.emptyDoubleVector(5)
      identstring = stypes.stringToCharP(idlen)
      found = ctypes.c_int()
      libspice.spksfs_c(body, et, idlen, ctypes.byref(handle), descr, identstring,
                        ctypes.byref(found))
      return handle.value, stypes.cVectorToPython(descr), \
             stypes.toPythonString(identstring), bool(found.value)